Well integrity: simple modelling
- Initial work suggests flow of gas up (or water down) is negligable
Coal seam gas wells are designed and constructed to ensure an environmentally sound and safe production of gas and other fluids. This includes a well integrity standard to prevent potential shallow gas migration. Management of well integrity is required throughout the life-cycle of a well in addition to finding solutions to reduce the possible risk of uncontrolled gas release. Although there are strict regulations and guidelines in place for CSG well integrity, it is important to understand the consequences for an unlikely well integrity breach event.
The two types of failure conditions used to test a well integrity breach were:
- A potential flow-path between a CSG reservoir and a shallow aquifer via a hypothetical cement micro-annulus, and
- A potential flow-path between a CSG well and a shallow aquifer via a hypothetical small hole in an intermediate casing string.
For this project the aim was to inform possible flow directions and rates for illustrative purposes only. This work will inform future studies on shallow gas migration and risk.
PROJECT OUTPUTS
- A short technical report of the modelling approach.
- A set of illustrative slides based on the report.
- Computer simulations of models and journal publication.
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